Several optimization-based strategies have been proposed for compliant mechanism design that do not rely on the experience or intuition of the designer. This paper demonstrates an optimization-based method wherein compliant mechanisms are modeled parametrically within an optimization and a finite element analysis package. Topological optimization is performed to minimize an objective function representing the fitness of the design. This methodology exploits the nonlinear nature of compliant mechanisms and augments optimization-based methods previously proposed. Using this method, constant-force mechanisms optimized for a displacement from 4% to 25% of the mechanism’s total length were predicted to remain within 3.58% of constant force. Results from the testing of fabricated mechanisms are: for 4-25% displacement, within 7.5% constant force; for 18-65% displacement, within 2.3%. Path generation mechanisms were designed with similarly encouraging results.